Animal litter containing twisted paper rods and method of providing a domesticated animal with mental stimulation

ABSTRACT

An animal litter is provided for simultaneously delivering urine-absorbent and mental-stimulating properties of the litter. The litter includes in combination a plurality of urine-absorbent particles forming a litter particulate component and a plurality of unfoldable polymeric cylinders constituting a polymeric cylinder component and intermixed with the urine-absorbent particles. The polymeric cylinders have a mean cylinder height of between 1 and 30 millimeters, a ratio of cylinder height to cylinder diameter of 1:1 to 12:1, and a strip length to cylinder height ratio of greater than 10:1. The litter particulate component is present relative to the cylinders in a volume ratio of 1:1 to 25:1. A process is further provided to mental stimulation and boredom reduction of a caged animal. The process includes providing the animal with the above inventive litter and allowing sufficient time for the animal to unfold a portion of the polymeric cylinders.

RELATED APPLICATIONS

This application is a continuation of U.S. Utility Application 11/939689filed Nov. 14, 2007, now U.S. Pat. No. 8,205,576 that in turn claimspriority benefit of U.S. Provisional Application 60/865,714 filed Nov.14, 2006, the contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention in general relates to animal litter, and inparticular to animal litter containing twisted paper cylinders, theunfolding of which providing an animal with a degree of mentalstimulation.

BACKGROUND OF THE INVENTION

There is a growing body of evidence that domesticated animals and inparticular laboratory animals exhibit behaviors that in humans areassociated with sensory deprivation, and depression. These abnormalbehaviors not only impact the well-being of an individual animal butalso have implications in studies involving such an animal owing to thephysiological effects of sensory deprivation and depression. In humans,sensory deprivation and depression have an effect on metabolism,cognitive function, immune response and other parameters relevant toclinical studies. The ability to provide a laboratory animal with adegree of mental stimulation is hampered by the requirements of studyprotocols that attempt to avoid introduction of new reaction variables,as well as the requirement in many instances that only sterilizedmaterials be brought into contact with a laboratory animal. Captiveanimals deserve an environment which is rich in social opportunity,mental stimulation, and physical challenges. Sterility conditions aretypically enforced in instances where an animal has beenimmunocompromised or otherwise carries a genetic defect rendering ananimal vulnerable to disease or infection.

With laboratory study requirements, litter provided to absorb animalurine and desiccate fecal material is one of a limited number ofopportunities to provide a source of stimulation to a confinedlaboratory animal. Prior art attempts have been made to include foldedsquares of paper with the intention that the animal would occupy timedelaminating and chewing or unfolding the small chips of paper.Unfortunately, such attempts met with limited success owing to thedisinterest of mice (especially male species) and rats confined withinlaboratory cages to actually play with the folded squares of paper. The1985 amendments to the Animal Welfare Act included provisions for thepromotion of the psychological well-being of nonhuman primates and forexercise for dogs. Today, many research, teaching and testing facilitieshave established environmental enrichment programs for all animalspecies. (awic.nal.usda.gov/nal_display/index) are representative ofthis effort.

Sheehan (U.S. Pat. No. 5,909,718) teaches a method of making particulateabsorbent material from waste paper for the use of the material as abase for animal bedding. The waste paper is shredded, mixed with waterand a binder, and dried to form solid paper particles having a diameterof from about 0.05 to about 2.0 centimeters. These have met with limitedacceptance owing to exposing laboratory animals to unknown substancesassociated with the waste nature of the paper, as well as the lack ofplay value afforded to animals.

Tucci (U.S. Pat. No. 4,038,944) provides a synthetic animal bedding inrecognition of the fact that natural bedding material must be replacedperiodically and is not reusable. Although having tried to solve priorproblems associated with the reusability of natural straw bedding, Tuccidisfavors straws and further requires that the synthetic plastic piecesbe arranged relatively parallel to the ground or bottom surface.

Similarly, Mochizuki (U.S. Pat. No. 6,405,676) teaches a twisted papercylindrical material as a urine-absorbing litter. However, this materialhas met with limited acceptance owing to a low density and asymmetricshape that makes scooping and handling difficult. Also, presumably owingto the uniformity of the material as being exclusively twisted papercylinders, sensory deprived animals are observed to be indifferent toplaying with the paper cylinders.

Thus, there exists a need for an animal litter product that engages theattention of a laboratory animal to occupy time and alleviate some ofthe symptoms associated with sensory deprivation and depression. Therefurther exists a need for such a litter capable of being sterilized andstill functioning as an effective animal litter product.

SUMMARY OF THE INVENTION

An animal litter is provided for simultaneously deliveringmental-stimulating and urine-absorbent properties of the litter. Thelitter includes in combination a plurality of urine-absorbent particlesforming a litter particulate component and a plurality of unfoldablepolymeric cylinders constituting a polymeric cylinder component andintermixed with the urine-absorbent particles. The polymeric cylindersare made of materials illustratively including cellulose, alkoxylatedcellulose, alginate, starch, and synthetic polymers. The polymericcylinders have a mean cylinder height of between 1 and 30 millimeters, aratio of cylinder height to cylinder diameter of 1:1 to 12:1, and astrip length to cylinder height ratio of greater than 10:1. The litterparticulate component is present relative to the cylinders in a volumeratio of 1:1 to 25:1.

A process is further provided to mental stimulation and boredomreduction of a caged animal. The process includes providing the animalwith the above inventive litter and allowing sufficient time for theanimal to unfold a portion of the polymeric cylinders.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of a prior art twisted paper rod;

FIG. 2 is a schematic showing the folding and twisting to form apolymeric fiber cylinder; and

FIG. 3 is a perspective representation of laboratory animal manipulationof an inventive litter.

DESCRIPTION OF THE INVENTION

The present invention has utility as an animal litter. With theinclusion of polymeric cylinders that an animal unfolds to form a strip,an activity is provided to the animal that occupies time and appears toalleviate behaviors associated with cage confinement. The resultantunfolded strips are routinely fashioned into nesting material byanimals.

As used herein, the term “polymeric cylinder” is defined to include atleast one ply of fibrous material axially wound, folded and wound,twisted, and combinations thereof into a cylindrical shape. It isappreciated that the polymeric cylinder is readily compression deformedasymmetrically to provide an overall conical or truncated conical shape.The fibrous material illustratively includes cellulose, alkoxylatedcellulose, alginate, starch, polyethylene, polypropylene, polyvinyl,polystyrene, Spandex, Lycra, rubber, fleece, or any combinationsthereof.

As used herein, an “animal” is defined to include a rodent such as amouse, rat, hamster, gerbil, and rabbit; a bird such as a quail,chicken, turkey, parrot, parakeet, canary, and finch: felines, such asdomesticated cats; and a primate such as a monkey, chimpanzee, andgorilla.

As used herein, the term “unfoldable” means the state of a polymericcylinder capable of being extended wholly or partially to form a sheetstrip.

An inventive animal litter includes in combination a group ofurine-absorbent particles forming a litter particulate component and agroup of unfoldable polymeric cylinders constituting a polymericcylinder component, whereas the cylinders are intermixed with theurine-absorbent particles.

The unfoldable polymeric cylinders retain moisture-absorbent propertiesnecessary for an animal litter while providing an activity for an animalin contact with inventive litter. An inventive polymeric cylinder isabsorbent of urine and formed of a material illustratively includingcellulose, alkoxylated cellulose, polyvinyl alcohol, alginate, andstarch. Preferably, the polymeric cylinder is formed of cellulosicpaper. In the event where the unfoldable polymeric cylinders of aninventive litter are concurrently urine absorbent, the cylinders arepreferably made of cellulose paper. A twisted fiber sheet rod is wellknown to the art and depicted in prior art FIG. 1 excerpted from U.S.Pat. No. 6,405,676. Alternatively, an axially wound polymeric cylinderis formed by rolling one or more material sheets around a central dowel,crimping or adhesively packing the free end of the sheet to the roll andcutting the resultant roll into a cylinder of a desired length. Anaxially wound polymeric cylinder at formation is depicted in FIG. 2 at10 as being formed by helically twisting a folded sheet 11 from a sheetstrip 12. It is appreciated that the unfoldable polymeric cylinders ofan inventive litter are able to absorb per unit area more liquid than acorresponding folded rectilinear structure formed of the same material.

A group of unfoldable polymeric cylinders according to the presentinvention has a mean height between 1 and 30 millimeters. It isappreciated that the mean height of the cylinders is chosen withrecognition as to the size and dexterity of the animal using theinventive litter. When fully unfolded and extended, each, polymericcylinder has a strip length. The strip length is at least 10 times theheight of a given polymeric cylinder. By way of example, a 3 millimeterhigh cylinder is formed through twisting, enveloping or rolling apolymeric sheet strip at least 30 millimeters in length. Morepreferably, the sheet material length is at least 15 times the cylinderheight. Still more preferably, regardless of the number of sheetsenveloped within a given cylinder, a ratio of cylinder height tocylinder diameter is from 1:1 to 12:1.

A group of unfoldable polymeric cylinders constitutes a polymericcylinder component of an inventive animal litter and is preferablyamenable to sterilization for use in conjunction with immunocompromisedor genetically mutated laboratory animal models for disease. Thesterilization techniques operative with the polymeric cylinder componentof an inventive litter illustratively include gamma radiation andthermal sterilization techniques such as those involving superheatedsteam or heated air. It is appreciated that sterilization of thepolymeric cylinder component can occur separately or in concert with theparticulate litter component.

The polymeric cylinder component of an inventive litter is amenable toincorporation of various adjuvants operative to enhance litterperformance and/or entertainment value. Adjuvants suitably incorporatedinto the polymeric cylinder component of an inventive animal litterillustratively include fragrances; dyes; odor suppressants such asbaking soda; superabsorbent polymer granules; flavorants such as sugarand fruit flavors; and nutrients. In the instance where a polymericcylinder component includes entertainment value enhancing adjuvants suchas dyes or flavorants, it is appreciated that the stimulation value isenhanced by irregular distribution of the adjuvant. Irregulardistribution is readily achieved by exposing the polymeric cylinderalong one edge or diameter for an amount of time sufficient to create anincomplete penetration of the adjuvant into the polymeric cylinder. Itis appreciated that an adjuvant is readily applied in the form of asolid, liquid, or solution with excess moisture being removed to arriveat a polymeric cylinder component moisture component with a preselectedlevel.

The litter particulate component of an inventive litter includes pelletsor granules of a litter material illustratively including bentoniteclay, corncob, paper fluff, as paper pellets, wood shavings, wood chips,wood pellets and derivatives thereof, diatomaceous earth, grass, straw,soy hulls, sunflower hulls, oat hulls, rice hulls, corn stalks, pecanshells, corn husks, spelt hulls, wheat chaff, dried distillers grain,and combinations thereof. Typical particle sizes of particulatecomponent to an inventive litter have a mean particle size of between 4and 40 U.S. standard mesh. Particulate litter component in addition tothe role as an absorbent also serves in the present invention todisperse and partly hide polymeric cylinders so as to create an activityfor a proximal animal to uncover and thereafter unravel a polymericcylinder. Representative particulate litter component compositions andmethods of formation, are provided in U.S. Pat. Nos. 5,000,115;6,053,125; 5,064,407; and 5,062,954. It is well known throughobservation that animals are afforded virtually no sensory stimulationthrough interaction with particulate litter. In order to provide thedesired mental stimulation to an animal, the particulate component ispresent in a volume ratio relative to the polymeric cylinder componentof from 1:1 to 25:1.

The unfoldable polymeric cylinders of the present inventive litter arepreferably combined to the litter particulate component prior to theirbeing presented to an animal in the form of a bedding so that the numberof times when the animal has to be disturbed for the delivery of thebedding material is kept at a minimum. It is also recognized additionalcylinders are optionally supplied to the animal independent of a litterchange. Depending on the number, size, and physiological conditions ofanimals housed in a cage or simply when a portion of the existingcylinders are wet due to urine retention, a supplemental supply ofunfoldable polymeric cylinders is optionally provided. It is understoodthat the supplemental supply is composed of cylinders that optionallydiffer from the replaced cylinders in at least one aspect with theaspect illustratively including texture, color, smell, shape, or anycombination thereof. By way of example, a soft rubber cylindrical rollwith or without a fragrance patch is provided to the animal in a littercomposition to replace an old cylinder component made of paper. This isintended to offer additional stimulation while maintaining themanageability of replacing an animal litter.

An animal, when provided with the present inventive litter, engages anactivity to reduce boredom, anxiety and to enhance mental stimulation.The activity involves relocation of polymeric cylinders from theinventive litter and systematic turning and unfolding of the cylindersto yield a polymeric strip. Typically, an animal removes one or morepolymeric cylinders from one location within the cage to another.Preferentially such cylinders have not as yet been saturated with urine.

An animal exposed to an inventive litter, in particular a rodent, isobserved to initially begin chewing an inventive litter polymericcylinder. Upon the animal discovering that the cylinder begins tounravel, animal handling and chewing of a polymeric cylinder becomespurposeful with the intent of rendering a cylinder as a strip. Thestrips formed from unfolding polymeric cylinders are then taken by theanimal to be segregated from the particulate component of the litter andto be used to form a hiding place as well as bedding. The inventivelitter replaces manufactured rigid hiding places with a moreinstinctively sought and natural material to the animal.

As shown with reference to FIG. 3, the inventive animal litter asprovided to an animal contains particulate component 12 and polymericcylinder component 14. An animal, a mouse M as depicted in FIG. 3,begins to interact with the inventive litter collectively depicted at16. The animal M chews polymeric cylinder 14 to produce a maceratedpolymeric mass 18. Typically the animal M begins to unravel cylinders toform partially unraveled polymeric fiber cylinders 20 and eventuallysucceeds in creating only unraveled polymeric fiber strips 22. Thestrips 22, partially unraveled cylinders 20 and macerated mass 18 invarying amounts are formed as a shelter 24 and/or a bedding mass 26. Asurprising aspect of the present invention is that male rodents, whichare more likely to exhibit abhorrent and antisocial behavior, are alsoobserved to engage in apparent play behavior with the polymer fibercylinder component of an inventive litter. The periodic inclusion offlavorant patches 28 and to a lesser extent colorimetric zones 30 alongthe length of a polymeric fiber strip formed into a cylinder is noted toenhance animal interest in the inventive litter.

EXAMPLES Example 1 Prior Art Bedding of Twisted Paper Rods Alone Versusthe Inventive Litter Combining Both the Litter Particulate Component andthe Unfoldable Polymeric Cylinders

200 grams of twisted paper rods of a mean length of 10 millimeters and amean diameter of 5 millimeters per U.S. Pat. No. 6,405,676 are laid flaton the bottom of each of the five separate cages of the comparativegroup. A total 200 grams of an inventive litter is laid flat on thebottom of five separate cages of the inventive group. The inventivelitter is composed of 20 grams of the twisted paper rods per U.S. Pat.No. 6,405,676 and 180 grams of dry corncob particulate with a mean sizeof 2.5 millimeters intermixed with the cylinders. All cages arestructurally identical and kept in isolation. To each cage, a male ratwith comparable weight, age, and physiological conditions is placed.

The following experimental parameters are examined: the first playperiod before the first resting observed; the length of the firstresting segment; the second play period between the first two restingsegments; and the length of the second resting segment. Table 1illustrates the results of the experiment. The term “play period” refersto a period of time in minutes during which a rodent is relativelycontinuously touching, kicking, and rolling the bedding object. The term“resting segment” refers to a period of time during which a rodent is inan idling position such as lying down, sitting, or merely walking. Eachtime period is presented as an average of five independent readings.Table 1 shows the relevant results with regard to this experiment.

TABLE I Average for Average for Comparative Group Inventive Group Firstperiod 8 minutes 15 minutes First resting segment 5 minutes  4 minutesSecond play period 5 minutes 15 minutes Second resting segment 10minutes   6 minutes

The substantial prolongation in playing times associated with theinventive litter is due to the following factors. The rodents in theinventive group first spend a good portion of time in digging andsegregating the paper cylinders away from the rest of the corncobcomponent. After the relocation is done, the rodent starts peeling andunfolding the paper cylinders. Later, the rodent remixes the partiallyunraveled paper cylinders with the corncob. It is noticed that noactivities of intentional segregating and remixing are observed with therodent in the comparative group.

Patent documents and publications mentioned in the specification areindicative of the levels of those skilled in the art to which theinvention pertains. These documents and publications are incorporatedherein by reference to the same extent as if each individual document orpublication was specifically and individually incorporated herein byreference.

The foregoing description is illustrative of particular embodiments ofthe invention, but is not meant to be a limitation upon the practicethereof. The following claims, including all equivalents thereof, areintended to define the scope of the invention.

1. An animal litter comprising in combination: a plurality of corncobparticles forming a litter particulate component; and a plurality ofunfoldable twisted paper cylinders constituting a paper cylindercomponent and intermixed with said plurality of corncob particles. 2.The litter of claim 1 wherein said plurality of unfoldable twisted papercylinders have a mean cylinder height of between 1 and 30 millimeters.3. The litter of claim 1 wherein said plurality of unfoldable twistedpaper cylinders have a ratio of cylinder height to cylinder diameter of1:1 to 12:1.
 4. The litter of claim 1 wherein a volume ratio of thelitter particulate component to paper cylinder component is between 1:1to 25:1.
 5. The litter of claim 1 wherein said plurality of unfoldabletwisted paper cylinders each have a strip length to cylinder heightratio of greater than 10:1.
 6. The litter of claim 1 wherein at least aportion of said plurality of unfoldable twisted paper cylinders has aplurality of spaced zones that vary in a property selected from thegroup consisting of: dye coloring, flavorant concentration, and anycombinations thereof.
 7. An animal litter comprising in combination: aplurality of corncob particles forming a litter particulate component;and a plurality of unfoldable twisted paper cylinders constituting apaper cylinder component and intermixed with said plurality of corncobparticles, wherein a volume ratio of the litter particulate component tothe paper cylinder component is between 1:1 to 25:1.
 8. An animal littercomprising in combination: a plurality of paper pellets forming a litterparticulate component; and a plurality of unfoldable twisted papercylinders constituting a paper cylinder component and intermixed withsaid plurality of paper pellets.
 9. The litter of claim 8 wherein saidplurality of unfoldable twisted paper cylinders have a mean cylinderheight of between 1 and 30 millimeters.
 10. The litter of claim 8wherein said plurality of unfoldable twisted paper cylinders have aratio of cylinder height to cylinder diameter of 1:1 to 12:1.
 11. Thelitter of claim 8 wherein a volume ratio of the litter particulatecomponent to paper cylinder component is between 1:1 to 25:1.
 12. Thelitter of claim 8 wherein said plurality of unfoldable twisted papercylinders each have a strip length to cylinder height ratio of greaterthan 10:1.
 13. The litter of claim 1 wherein at least a portion of saidplurality of unfoldable twisted paper cylinders has a plurality ofspaced zones that vary in a property selected from the group consistingof: dye coloring, flavorant concentration, and any combinations thereof.